The heater works for about an hour after the car.

The heater works for about an hour after the car is initially started. Then the air stops But the blower still sounds like it is working. When I come to stop the actuator doors sound like close doors close making a very loud air rushing noise but still no airflow.

If I shut the engine off for 30 to 45 minutes everything resets to normal. We are on 1300 mile trip home and cannot repair on the road but is there a way to get the doors to open manually or is this a relay or vacuum hose issue